Mercury MerCruiser Heat Exchanger to Port Elbow Hose 32-864543
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Mercury MerCruiser Heat Exchanger to Port Elbow Hose 32-864543
Part Number: 32-864543 (bare ref: 864543)
Brand: Mercury / Quicksilver
Product Type: Molded Cooling Hose (OEM)
System: Closed-Cooling / Freshwater-Cooled Exhaust Circuit
Position: Heat exchanger outlet to port-side exhaust elbow
GTIN / UPC: 745061559226
Quantity Required: 1 per engine
Approximate Weight: 300 g
What This Part Does
The 32-864543 is a genuine OEM molded hose that connects the heat exchanger outlet to the port-side exhaust elbow in selected MerCruiser closed-cooling (freshwater-cooled) inboard engines. It is a position-specific molded hose — the corresponding starboard-side connection uses a different part number and is not interchangeable with this hose.
Compatible Applications
Confirm your engine model and serial number before ordering. Mercury used several different molded hoses across the closed-cooling circuit, and hose routing varies by engine configuration.
- MerCruiser 5.7L MPI Horizon MIE
- MerCruiser 6.2L MPI Horizon MIE
- MerCruiser 350 MAG MPI Horizon MIE
- MerCruiser MX 6.2L MPI Horizon MIE
- MerCruiser 383 MAG Stroker Inboard
- MerCruiser 357 Horizon Inboard (remanufactured applications)
Serial Number Notice
Do not order by hose appearance alone. Mercury uses multiple molded hoses in the same closed-cooling circuit — each with a specific routing and connection point. Confirm by engine serial number and diagram position. Do not confuse 32-864543 with:
- 32-864544 — Heat Exchanger to Starboard Elbow (different side)
- 32-864886 — Heat Exchanger to Circulating Pump
- 32-863611 — Sea Pump to Transmission Cooler
When to Replace
- Cracking, surface checking, or hardened rubber
- Soft, swollen, or spongy areas along the hose body
- Leakage at either connection point
- Chafing, abrasion, or distortion at clamp locations
- Internal collapse or restriction suspected
Inspect closed-cooling hoses whenever the heat exchanger or exhaust elbows are serviced. Replace as a set with the starboard-side hose if the engine has high hours or either hose shows age-related deterioration.
Installation Notes
- Inspect the heat-exchanger outlet fitting, port exhaust elbow connection, and hose clamps during replacement
- Ensure the hose is fully seated at both ends and correctly routed
- Keep the hose clear of hot surfaces and moving components
- Tighten clamps to the torque specified in the Mercury service manual
- After installation, run the engine to operating temperature and inspect the full cooling circuit for leaks
Part Number Cross-Reference
- Current OEM: 32-864543
- Bare Reference: 864543
Note: Mercury diagrams also list 864953 and 864973 at the same heat-exchanger-to-port-elbow diagram position on certain configurations. These are not universal replacements for 32-864543 — confirm against your engine serial number and diagram before ordering.
Parts Desk Insights
Best use case: Order 32-864543 when you have confirmed port-side elbow hose failure on a MerCruiser closed-cooling inboard and have matched the part number to your engine diagram. It is most commonly replaced during heat exchanger service or when the engine is pulled for elbow inspection.
Common issues: The most frequent ordering mistake is confusing the port-side hose (32-864543) with the starboard-side hose (32-864544) — they look similar but route to different sides of the engine. Always identify port vs. starboard before ordering. A second common issue is ordering only one hose when both sides show the same age and deterioration — if one is cracked, the other is likely close behind.
Related Parts
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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